The present disclosure generally relates to the field of vibration analysis. More specifically, the present disclosure relates to a technique for high-speed video vibration analysis of structures.
Nowadays, vibration and structural health testing in the industry and, more specifically, ground and flight testing in the aeronautical industry, are based fundamentally on devices known as accelerometers. Despite being very accurate and reliable, accelerometers need long preparation and installation time, demand highly qualified operators, load the structure under test with their own mass (thus altering the vibration response of the structure) and can only measure at discrete points.
More modern non-contact technology is represented by Laser Doppler Vibrometers (LDVs). LDVs are mainly applied in the automotive industry, although aeronautical, civil, acoustic, defense and security fields make also use of this technology to a certain extent. The main drawbacks of LDVs are affordability (very high price), operability (LDVs' performance worsen with exposure to external daylight and fall off rapidly when the distance to the target increases), and versatility (they are active optical systems, characterized by high power consumption and typically “bulky”, i.e., they cannot be operated in limited space or too far from the surface to observe).
Moreover, only targets with a limited size (typically in the order of one square meter) can be tested with LDVs, and the surface under observation must be perpendicular to the laser beam.
Thus, there is a need for an improved technique for vibration analysis of structures.